Growback 5: Daphne restores Dalyenong

A rare stand of old-growth Red Ironbarks in Dalyenong Nature Conservation Reserve.

If you behave badly, you might be reborn as a colonizing shrub. If you do, then central Victoria’s got everything you need – low rainfall and bad soil, all within 2 hours drive from Melbourne.

Proximity to a big city is a boon for estate agents and regenerating plants. Agriculture isn’t very profitable where soils are poor and rainfall is low. If city folks find the poor soils attractive for bush blocks and retirement properties, then land prices rise above their agricultural value. Economic forces then drive an inexorable transition from traditional agriculture to ‘multi-functional’ or ‘amenity’ landscapes. As the crops and livestock are removed, native trees and shrubs can establish. This natural regeneration restores vegetation cover faster (and cheaper) than we could achieve by any other means.

It’s fascinating to see different species riding the wave of regrowth in different regions. In earlier posts, I’ve described regeneration by Drooping Cassinia, Burgan, Grey Box and Red Gum, all of which have regenerated across large areas after cropping or grazing were removed.

Last week I visited a big area of natural regeneration near St Arnaud, in west-central Victoria, where yet another native shrub has regenerated across 100s of hectares. From a conservation perspective, its a very uplifting region. A patchwork of regrowth and small remnants is creating new linkages between the large, isolated conservation reserves.

Remnants (dark green) and regrowth (paler in color) re-link reserves in the St Arnaud region. The numbers on the photo show the locations of other photos below (Source: Google Earth).

One of the best small remnants in the region is the John Colahan Griffin Nature Reserve, which was purchased recently by the awesome non-profit organization, Bush Heritage Australia.

Bush Heritage Australia’s wonderful property.

Among it’s many splendors, the reserve contains the biggest Long-leaved Box (Eucalyptus goniocalyx) that I’ve ever seen in my life.

Is this the biggest Long-leaved Box (Eucalyptus goniocalyx) on the planet?

The Nature Reserve is surrounded by paddocks, remnants and regrowth. Many regions in Victoria were ring-barked and cleared in the 1800s. By contrast, much of this region was uncleared (or was cleared and had already regenerated) when the first air photos were taken in the 1940s. If nothing more, this late clearing indicates the poverty of many soils in the region.

John Colahan Griffin Nature Reserve and surrounds in 2011 (Source: Google Earth).

It’s fascinating to see how vegetation has come and gone over the past 70 years. The red polygons on the photos above and below encircle patches of vegetation that existed in 1946. On the Google Earth photo above, cleared areas inside the polygons were cleared after 1946, and areas of regrowth outside the polygons re-colonized after the 1940s. The landscape is a patchwork of remnants and regrowth of differing sizes and ages.

The same area in 1946. The red boundaries show the main patches of vegetation at the time.

Some of the vegetation on the 1946 air photo was probably cleared earlier still, and had regenerated before the photo was taken. The right hand polygon (above) contains a large patch that looks like young regrowth, for example.

The natural vegetation in the region varies from Red Ironbarks on the dry ridges, to Yellow Box and Red Gum on the more fertile creek flats. Dalyenong Nature Reserve, in the east of the region, contains some fantastic stands of old-growth Ironbark forests. By any reckoning, soil fertility doesn’t get much worse than this. Fortunately for agriculture, the lower slopes are more productive and support fertilized crops and pastures.

Cleared cropland east of Dalyenong Nature Conservation Reserve.

Natural regeneration performs a series of fantastic landscape functions in this region. It creates linkages between reserves, increases the effective size of reserved patches, and buffers the edges of reserves, as can be seen in the following photos.

Regrowth extends the size of bushland in the Daylenong Reserve and buffers the southern boundary from agricultural use. (Source: Google Earth).

Most of the regrowth patch shown above was cleared pasture in 1946.

The same area in 1946; most of the paddock was treeless.

A younger patch of regrowth performs the same function on the southern edge of the John Colahan Griffin Nature Reserve.

Regrowth south of the John Calahan Griffith Reserve. To help you juxtapose the two photos, the three red circles show trees that are visible in both photos.

Once again, this paddock was almost completely devoid of trees and shrubs in 1946.

The same area in 1946. Note the three trees circled in red.

So what plants grow in the regrowth patches? The dominant trees vary, but the dominant understorey plant is the native shrub, Daphne Heath (Brachyloma daphnoides). Brachyloma is a widespread native shrub, but I’ve never seen it colonize such large areas before. Unlike many heathy epacrids, it doesn’t need fire to stimulate seed germination, and can regenerate abundantly in unburnt areas.

The beautiful Daphne Heath (Brachyloma daphnoides). Source: Gouldiae’s Blog.

Daphne Heath has beautiful perfumed flowers. When 1000s of plants are in full bloom in spring, this must be the most fragrant regrowth in the state.

An old stand of regrowth dominated by Daphne Heath (past it’s flowering peak unfortunately) below scattered Red Stringybark and Long-leaved Box.

From St Arnaud in the west to Rushworth and Yea in the east, native trees and shrubs have re-claimed 1000s of hectares of retired agricultural land, creating the biggest areas of landscape restoration in the state.

If I’m ever re-born as a colonizing shrub, I’d choose to be a Brachyloma. In my next incarnation I can personally contribute to restoring an amazing landscape – and I’d smell really good at the same time.

Acknowledgements

I am most grateful to Peter from Gouldiae’s Blog for permission to use his great photo of Daphne Heath. Peter’s great site on natural history in Gippsland is well worth a visit.

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